I have recently been riding bmx, racing to be more specific. I ride around my neighborhood a lot when im not at the track and have noticed this loud clanking noise. I didn't know where it was coming from at first. Thought it was maybe the pedal. But then I started paying more attention to it. It happens on my right foot when I pedal. This happens about every 10-15 minutes and sometimes I don't get it for an hour or two. When I was at the track I was standing up at the gate with my right foot forward. Then it happened. I was simply standing there and it made the loud clank noise, but then I found out where the problem is.(sort of). When it happened my right foot went down one crank. My foot went foward with out the tire or bike moving. What's the problem? Will it cause future damage? My guess is that the crank is slipping and not engaging. I have a 3 piece cliq crank. I'll try to discribe the sound a little better. It sounds like your hitting the bottom bracket with a rock or tapping it with your finger.

It's a little hard to tell from your description, but it sounds like something to do with the chain -- slipping a tooth, a "frozen" link flattening out or some such. But with the 3-piece crank it could be a crank arm loose on the shaft (which is a more serious problem). To check for that, grab the crank arm and try to move it in and out. Any motion at all relative to the shaft is not good.
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Daniel R HicksAug 15 '14 at 19:01

Thanks for the reply, I checked the crank arms and they don't move so that's good. Now I just need to pay close attention to the chain. That might be the problem. I'm not sure if it would make that noise though. I don't have another chain to test it either. The only other chain I have is filled with grease from a 1970 mongoose :)
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DylanAug 15 '14 at 19:46

Well, I've heard of using goose grease in a pinch, but never mongoose grease. (Thoroughly clean and oil the chain, and see if that helps.)
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Daniel R HicksAug 15 '14 at 20:27

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The symptoms you describe in the start gate suggest to me that your freewheel may need replacing. BMX racing is pretty tough on single speed freewheels.
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Fred the Magic Wonder DogAug 15 '14 at 21:04

1 Answer
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I've had similar problems (clicking on the right side down stroke) before, and it is probably the bottom bracket. But the first thing to do is to check and make sure that you don't have a loose bolt/ nut somewhere. This could be in your pedal, the crank, or somewhere else in your drivetrain. If you make sure that everything is tight and it still doesn't go away it's time to try replacing your bottom bracket. It's a pretty easy fix, but does require a special tool. http://sheldonbrown.com/tooltips/cartridge.html

Thanks, I haven't been able to try anything yet because it's been poring rain all day. But i will make sure everything's tight, I've done everything but look at the chain. I won't know until I get to ride again.
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DylanAug 16 '14 at 1:13